Both here and in the Río Negro the humidity and consequent quantity of insects make all agriculture impossible. Everywhere you see large ants, which march in packed columns and devour all cultivated plants that are soft and juicy, while in the jungle they can find only woody stalks. If a missionary wants to plant lettuce, or any other European vegetable, he has to hang his garden in the air. He fills an old canoe with good earth and hangs it 4 feet above the ground with rope made from chiquichiqui palm or, more commonly, rests it on some scaffolding.